Actuator



Dec. 6, 1949 P. G. FRERER 2,490,040

ACTUATOR Filed Feb. 8, 1945 2 Sheets-Sheet 2 INVENTOR. PAUL G FRERERJJMM Patented Dec. 6, 1949 ACTUATOR Paul. G. Frercr; Towson;Mrkeassignor tos-Perfex Corporation,- lvlilwaukee, Wis., a corporationofWisconsin Application February a, 1945; Serial No-;- 5715, 815

1 Claim.

Fig. 6-is a:-sectional.'vlew taken on line: 6-4;: of-

Fig. 5;

Referring: to the: drawings, reference; character; I indicates a basecasting which .is. preferably generally: L-shaped', having; a: generallyrectanagul-ar base por-tion- 2 and;atransverse: portion 3:

The transverse portion-.3 isrormedwith laterally extending-ears -4iand 5and serves-as 'a mount for.

an electric motor and: speed ireductionzunit gen erally indicated as 62gear train "unit =may =be ot any suitable type come merci-ally-availableand forms no part of the in?- ventiorr. This unit is suitably'secured toa mountingflange -1, whichrinturn is secured to the-.ears-land S bymeansof bolts' 8 and 9; Theoutput shaft I'O ofthe-electric motor. unitextends into an open-- ing H which is formed in the transverse portion 3ofthebase member:

As shown more-.clearly in -Fig; 3, the transverse portion of the base isformed with an enlarged opening 1 2 for receiving'atubular housingmember l3. This housing member-abuts against" a shoulder Wand is heldiinplaceaby-means of a set screw |5.. This tubular housing member at its.

other end .is provided with a cap l6 (Fig: 5) whic'lris h'eld inpiacebyat'set screw IT. The -reap 6 is provided with a'circularopening whichserves astaguide fora longitudinallyjmovable shaft :1l8. The housing.member is also provided 'I with: an elongated slot |9;' the purpose ofwhich will become apparent as this description proceeds.

The shaft ll! of the electric motor unit fits into a hollowed outportion 20 of a rotatable shaft 2| which is provided with screw threads22. Preferably the motor shaft is slotted so as to receive a pin 23secured to the shaft 2|, this providing for This. electric motor and:

2 dIiViHg -ShaftiZbY thB shaft ID. The left hand end or theshaft 2| issupported by a bearing 25 whichfisspressedzinto'an opening in theshoulder Hlnof the; base. This bearing is formedv with a flange 25:which abuts the shoulder l4 and also which-.serves'l'as a thrusthearing. The shaft 2| is secured to a collar-21 which preventslongitudinalmovement of this shaft. This collar 21 isinterposedbetween.thrust bearing washers 28 andii29s It will benoted-that the thrust in one direction is restrained by the thrustbearing member 26: and. that thrust in the opposite direction is:restrained by-washers 29 which bear against thezmotor mountingflange I.

The threadedportionofthe shaft 2| fits into a= traveling nut 32-.whichis of approximately the same. diameter; as the internal diameter of thetubular housing member l3. Thistraveling nut 3-2 .-is:,p rovided withathreaded recess 33 which; receivesthescrew-threaded end of thelongitudinally-movable shaft I8. The shaft I8 is additiona1ly.-he1d-.-intplace in nut 32 by means of a set screw-aonstud: 34 whichextends upwardly through the elongated .slot H! in the housing member.It

willtbe; apparent that I the: longitudinally movable shait|8is supportedand guided in its movements at two points, namely by the traveling nut32 and. bythe; cap, .-|6;at1the end of the housing I3.

The longitudinally movable shaft I8 is providedv witn-anaeyelet 35 atitsouter end which may be attached-totanyr deviceeto be actuated, suchas a valve-stem, damper lever, etc.

When the-electric motor 6 operates in one direc'-'- tion it rotates thescrew-threaded shaft 2| in thensame direction which causes the travelinnut.32 to-travelttothe right. This traveling nut is prevented-from.rotating; by engagement of the pil 34 with onei-side voffisl'ot I9. of;theshaft |8=outwardlyimparts a thrust on the shaft-.22 in.-the=.opposite direction, which thrust:

istakenup by -the-:thrust washers 29. When the electric motor 6 operatesin the reverse direction theitraveli-nginutis caused to move inwardly orto the left; thus pulling the-shaft |8 inwardly. This impartsa thrust onthe shaft 2| which is taken up; bv'the thrust bearings 26 and 28,

For different'applications of the actuator different. amounts-of.-travel are required. For example-ifthe actuatoris used to operate alarge damper it may be necessary to utilize substantially the entiretravel of the motor. On another application or installation where theactuator 0perates a valve or stoker feed lever, a smaller portion of itstravel may be required. In order to provide for complete flexibility inapplication, this The movement invention provides a limit switchactuating mechanism which is readily adjustable. This limit switchmechanism will now be described.

Secured to the top of the transverse portion 3 of the base member is aplate 40. This plate carries a pair of limit switches 4| and 42 whichare preferably of the enclosed snap action type. These switches 4| and42 are located so as to face each other with their push buttons 43 and44 substantially in alignment. These push buttons are actuated by meansof a bell crank member 45 which is hinged to a post 46 secured to theplate 40. This bell crank member 45 preferably carries spring members 41and 48 which'engage the push buttons 43 and 44 respectively.

The other arm of the bell crank member is attached by a pin 49 to alongitudinally movable actuator 59. 59 is supported by the bell crank45. The right hand end of this actuator is supported by the collar l6(Fig. and is freely held in place by means of a shoulder screw 5|. Asshown in Fig. 6, the limit switch'actuator 50 is preferably of achannelled configuration and is provided with an elongated slot 52. Theactuating member 50, it will be noted, is mounted adjacent and parallelwith the elongated opening [9 in the housing 13. The slot 52 in theactuating member 50 is substantially the same length as the slot I9 andis in approximate registration therewith. The elongated slot 52 servesto receive a pair of adjustable abutment members 55 and 56. Eachabutment member may be formed of a pair of plates 5? and 58 and a setscrew 59 which is screw-threaded into the plate 58. It will be apparentthat either abutment member may be moved simply by loosening screw 59and moving the abutment to the desired location and retightening screw59. Preferably the screws 59 are clinched so as to prevent completeremoval of the abutments from the member 56. The abutments 55 and 56 areengaged by the pin 34 which is carried by the traveling nut 32. As thetraveling nut 32 travels to the left, it engages the abutment member 55,thereby moving the member 50 longitudinally to the left. This rotatesthe bell crank counterclockwise as seen in Fig. 1, this pressing thepush button 44 of switch 42 inwardly for opening this switch. Thisswitch 42 is wired in the motor circuit so as to prevent further travelof the motor in this direction. When the motor is operating in theopposite direction it will eventually cause the pin 34 to engage theabutment member 56. This will move the member to the right and rock thebell crank 45 clockwise, asseen in Fig. 1, which pushes plunger43inwardly for Opening the limit switch 4|, which arrests furtheroperation of the motor in this direction. It will be apparent that byadjusting the positions of the abutments and 56 on the actuating member'59, the limits of motion of the shaft l8 may be determined. 7

Preferably the limit switch actuating member 53 is covered by a housing6|, one end of which is secured to the cap l6 by screw 62. The other endof this housing is attached to the base by screws 63. Also the electricmotor 6, limit switches 4| and 42, and the terminal block 65 areenclosed by a cover 66, this cover being generally about its pivot tocompensate for the curved path of movement of the lever.

In such case the unit will be mounted solely by means of a screw passingthrough the eyelet 61. In other installations it is desirable to havethe actuator unit rigidly mounted. For such installations the unit willbe mounted both by the eyelet 61 and the mounting The left hand end ofthe actuator I bracket 68.

- From the foregoing description it will be apparent that the presentinvention provides a simple and rugged actuator device which may bereadily adapted for a large variety of difierent applications. Whileonly a single embodiment of the invention is shown; it will be apparentthat many changes may be made in the construction illustrated withoutdeparting from the invention. It is therefore desired to be limited onlyby the scope of the appended claim.

What is claimed is:

An actuator comprising a generally L-shaped base member having alongitudinally extending portion and a transverse portion, saidtransverse portion having an opening therethrough, a motor and geartrain unit mounted on one side of said transverse portion and having anoutput shaft in alignment with said opening, a tubular housing member onthe other side of said base member and in alignment with said opening, arotatable threaded drive shaft within said housing and arranged to bedriven by said output shaft, a hollow longitudinally movable shaftmember surrounding the drive shaft and in threaded engagement therewith,said hollow shaft member being guided in its longitudinal movement atleast partially by said housing member, a pair of limit switches forsaid motor, operating meansfor the limit switches comprising alongitudinally movable elongated limit switch actuator extendingadjacent the housing member and parallel thereto, the housing memberbeing formed with an opening adjacent said elongated member, meansattached to the hollow shaft member and extending through said opening,said last mentioned means preventing rotation of the hollow shaft memberand engaging said limit switch actuator.

PAUL G. FRERER. REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS McCoy Jan. 9, 1945

